She earned a standing ovation at Conservative party conference with a scathing assault on a "culture of excuses" in state education, and won roars of approval for singling out liberal guilt as the cause of black children's under-achievement.

When she returned to her school, deputy head Katharine Birbalsingh swiftly found she was out of a job after being confronted over pictures of children she used to illustrate her speech.

Now Birbalsingh has been approached by the Swedish government. Sweden pioneered "free schools", a policy that has been adopted by the coalition, and is also in the throes of a backlash against immigration, opening up a possible role for an educationalist with a mixed-race background. She may also take up the headship of a free school in England.

"I'm considering a few offers, and I'll make my decision and what I really want is to be back in a school by January," Birbalsingh said in an interview with the Guardian. "We'll see what happens really. There is this possibility of Sweden, which I think would be very interesting, although really I want to stay here."

If she did run her own school, it may come as no surprise that she would promote "traditional subjects" at the expense of less academic ones. She would also ignore Ofsted. "The rules that inspectors have about teaching, is an absolute nonsense."

Birbalsingh does not pull her punches. As well as Ofsted, Birbalsingh blames the welfare state for children lacking aspiration, and criticises unions for shielding bad teachers. "The problem with unions is that they have a one-size fits all policy and whether you're a good teacher or a bad teacher, the union will come in and defend you. Its very difficult to fire a teacher or a member of the support staff, it takes a long time and a lot of energy and a lot of heads just don't have that kind of energy … I don't believe that jobs should be forever."

Birbalsingh also accuses "white liberals" of defending a culture in which lawyers fight to get excluded black children back into school "because white people feel so guilty about any kind of racism".

Black people in Britain are being "duped by the white liberal", she said.

Birbalsingh, who teaches French, is of mixed Indian Guyanese and Jamaican origin. "I'm saying that the white middle class can sometimes feel very guilty about being white and middle class," she said.

"The same thing happens with regard to the poor as it does with regard to blacks, right? And because they feel so guilty, in order to alleviate that guilt, they take a paternalistic approach towards the poor and black people and rather than allowing black people to take responsibility for themselves and pull themselves up by their own bootstraps and look after themselves they think they must help us, same with the poor. I say 'us' because I'm black, I'm not poor, and I'm offended by it."

Introduced to Tory party conference by her first name only, Birbalsingh spoke ahead of the education secretary, Michael Gove, and declared that teaching in the state sector had led her from being a Marxist at Oxford to voting Conservative for the first time in this year's election.

When she returned to her job at St Michael and All Angels Church of England Academy in Camberwell, south London, she faced criticism over the pictures she had shown to the crowd, as well as whether her critique of the state system was disparaging to the school. "Maybe if I hadn't used pictures I wouldn't have got a standing ovation, who knows? Because it makes it real, you can see the kids; it's their story, it's not mine."

She said she secured the parents' permission and told them in her letter that the event would be televised.

"I wasn't expecting all of this, had none of this happened it would have been fine, you know, it would have been like every other talk I've ever given.

"Its just that all of this happens. So in that sense I regret it, but I didn't know 16,000 people were going to watch my speech on YouTube, not in a million years did I ever imagine that."

She is unrepentant. Instead, parting with her employer appears to have fired her up. "I don't think I've lost any teaching friends as such, no, and you know why? Because they know I'm telling the truth, I would never lose teaching friends and the other thing I haven't lost are black friends. I wouldn't lose black friends and I wouldn't lose teaching friends and that's because they know I'm telling the truth. Its my white liberal middle-class friends that I've lost."

But she has gained at least one friend: Gove rings up to check on her. "This has been a real learning curve for me, because I used to think the Tories were really evil. I used to think like the rest of the lefties, you know, and what I have discovered is that they're really nice people."

What she said

Extracts from Katharine Birbalsingh's speech to the Tory party conference

Anger management

"This is Kane. The other day he was in trouble and was spending his lunch hour with me. His best friend Mitchel approached, wanting to talk to him and I said he couldn't because Kane was being punished. Mitchel responded with: "But it isn't Kane's fault Miss, he was born with anger management," and Kane said, "Yes miss, it isn't my fault, I AM anger management." Notice how these boys don't even know what they're saying. But their words reveal a deeper culture of excuses."

Race

"If you keep telling teachers that they're racist for trying to discipline black boys, and if you keep telling heads that they're racist for trying to exclude black boys, in the end, the schools stop reprimanding these children."

Voting Conservative

"At some point in history, the left did enormous good for the teaching profession, and so we teachers tend to be blinded by leftist ideology. I, too, have been a victim of such thinking, and I come to you today, finally, ready to overthrow the shame that I have felt, literally shame, because in the last election, I voted Conservative."